The Effect of the Light Activation Mode on Incompatibility between One-Bottle Adhesives and Light-Cured Composites: An In-Vitro Shear Bond Strength Study

Adverse surface interactions between one-bottle adhesives and self – cured composites may occur similarly with light-cured composites during the use of different modes of light activation.This study examined the effect of different light activation modes of light-cured composite on the shear bond strength of 2 one-bottle adhesives with different acidity to the dentin. This experimental study was performed on 110 extracted sound molars. Then, the teeth were randomly divided into 10 equal groups (n=11). One-Step plus (OS) and Prime & Bond NT (P&B NT) were used and followed by respective composite application in 5 light- activation modes of soft conventional, Soft-Start I (SSI), Soft-Start II (SSII), Pulse-Delay I (PDI), Pulse-Delay II (PDII). Then, shear bond strength (SBS) test was performed, using an Instron at 1 mm/min. The SBS was recorded in MPa. Statistical analysis included two way ANOVA with a significance level of 0.05.The highest SBS (MPa) was shown in OS conventional group (19.62) and the lowest in P&B NT, PDII (5.43). In each group of 5 curing mode, mean SBS in P&B NT was significantly lower than that in OS as follows: In conventional; P&B NT (17.27) vs OS (19.82) in SSI; P&B NT (10.89) vs OS (13.09) in SSII; P&B NT (14.48) vs, OS (18.79) in PDI; P&B NT (5.93) vs OS (11.97) and in PDII; P&B NT (11.82) vs OS (16), (p <0.001). In each of 2 adhesives, ranking of SBS from minimum to maximum was as follows: PDI